1. Field of the Invention
This invention generally relates to beverage making systems of the type in which freshly brewed hot tea extract; is added to and mixed with cold water to make the final beverage.
2. Discussion of the Prior Art
Fresh brewed iced tea makers or fresh iced tea making systems, brew an extract of tea by selectively passing hot water from a hot water, tank through a brew basket containing the dry tea ingredient. The components of the dry tea dissolve into the hot water to form a concentrated liquid abstract of tea, or tea abstract. This tea abstract is then added into a mixing and dispensing urn in which the abstract is mixed with cold water.
Generally, cold water from a public water source is used to fill the hot water tank to a preselected level needed for brewing the abstract, and an electrical heater in the tank heats the water to a preselected temperature needed for proper brewing. During the brew cycle, the level of hot water in the tank is reduced by the preselected amount of the hot water that is withdrawn. The cold water from the public source that is used to fill the hot water tank is also used to directly add the diluting water to the mixing and dispensing urn.
The passing of water into and out of the hot water tank is via a fill valve and a brew valve, respectively, and the passing of diluent directly into the mixing chamber is via a third, diluent valve, or mixing valve. A pressure regulator in-line between the water source and the diluent valve is required because the measurement of the quantity of water passed directly to the mixing chamber is based on timing the period that the diluent valve is opened during a uniform flow rate.
The fill valve is controlled by a level sensor to pass water to the hot water tank until it is filled with water to a preselected level of the level sensor. Then the water is heated to a preselected temperature needed for proper brewing by energizing the electrical heating element. During the dispense period, the brew valve is opened to drain a preselected fixed amount of hot water through a spray head into the brew basket containing the tea or other ingredient. Neither the amount of hot water that is passed through the brew basket nor the amount of cold mixing water that is passed directly to the mixing chamber may be changed to accommodate different brewing conditions or to make different total amounts of beverage.
While this known brewing system functions successfully to make fresh brewed iced tea, it has some limitations and disadvantages of various types. The dry tea ingredients are often prepackaged in standard quantities such that the amount of tea cannot be changed by less than the incremental quantity of an entire package. If loose tea leaves are used that are not prepackaged, the quantity of dry ingredient can be changed by small amounts if desired but this requires the time, training and effort and potential inaccuracy of measuring the quantity of tea desired. Consequently, it is not easy to change the strength of the tea by changing the quantity of dry tea ingredient that is place into the brew basket.
Moreover, in the known iced tea maker, neither the amount of extract nor the total quantity of iced tea created by mixing the extract with the diluting water or the ratio between the extract and the diluent may be changed. Consequently, the strength of the resulting quantity of iced tea may only be changed by changing the quantity of dry tea ingredient used during the brew cycle to brew the extract. As noted above, this is not an easy thing to do and to do repetitively with the same quantity to maintain consistency. The problem becomes worse when different types of teas are used with one system at different times that are inherently different in strength of flavor, color, and other characteristics.
Another problem with known ice tea brewing systems is that there is a relatively long recovery period after the conclusion of preparation of one batch of iced tea before another brew cycle can be started. The tank from which the hot water is drawn cannot be replenished until all of the desired quantity of hot water has drained out of the mixing chamber. Because the tank is emptied or drained during the dispense period, the rate of draining becomes less and less as the level of water in the tank is reduced. At the end, there is virtually no head pressure, and the hot water merely drips out of the hot water tank. This water then must seep through the ingredient, and as a result this drip period may extend substantially beyond the time that the dispense period has ended.
Then after the hot water tank has been fully emptied, it can be replenished with a new fill of the preselected amount of cold water as needed to begin another brew cycle. Then there is a further delay before the cold replenishment water that is added to the hot water tank is heated to the preselected minimum temperature needed for a proper brew.
The total length of the brew cycle is thereby extended and the throughput of the brewing system, i.e. the maximum quantity of tea that can be made in an hour when used repetitively to make as much beverage as possible over a period of multiple successive brew cycles, is significantly decreased.
The known iced tea brewing system has other disadvantages associated with solenoid controlled valves that are used for control of the flow of hot water into and out of the hot water tank. As noted, the known tea brewing system uses three valves including a brew valve, or dispense valve, interconnecting the hot water outlet to the brew basket through a spray head. The brew valve dispenses hot water from the hot water tank to a spray head overlying the brew basket that sprays the hot water onto the top of a layer of tea within the brew basket. Disadvantageously, because the brew valve is passing hot water it is subject to becoming clogged with calcium and other mineral deposits that condense out of the hot water an on to the surfaces of the brew valve during evaporation. This is generally referred to as “liming”. This liming can interfere with they dependable operation of the brew valve to either open or close and thereby create potential safety hazards. In the past, preventative or responsive maintenance and possible valve replacement or the use of water softening chemicals and filters have been required to address this liming problem.
The inventors have noted that the other two valves, the fill valve and the mixing valve, are on the cold water side and do not suffer from liming to the same relatively high degree as does the brew valve.
In all known tea brewing systems all measurements are made by one of two different techniques. In one technique, a known quantity of water is dispensed by lowering the water within a container between two levels associated with the amount. In the second technique, the hot water is dispensed into the brew basket at a uniform rate by maintaining a preselected pressure level in the hot water tank, and then the brew valve is opened open for a for a total preselected time period corresponding to the desired amount of hot water to be added.